The Women's March on Washington is shaping up to be one of the biggest mass mobilizations in United States history, and it's got a speakers' lineup to match its lofty expectations.

Longtime activists Angela Davis and Gloria Steinem are scheduled to speak, along with younger activists like Janet Mock, Ai-jen Poo and Melissa Harris-Perry. Actresses America Ferrera and Scarlett Johansson are also slated to speak.